Hi. I have finished the first prototype of the lightweight KFM3 wing for my UDB2 / Matrixpilot UAV. The wing is made entirely out of Polystyrene. The benfits of this wing are: wide AOA range, wider stable CG range since lift is produced farther back on the wing surface, no aileron reflex needed so lower aileron reflex drag. I will add vinglets to reduce wingtip vortexes and drag due to vortex leakage out from the rear KFM surfaces.

This design should also give a low wingloading for autopiloted photo missions in low speed.

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  • Hi Chris. The step may probably be too large. However I think I recall that I based the step measurements on the wikipedia article about kfm. Something about percentages of the height, if I recall correctly.  I haven't flown it yet. However I have now attached a carbon fiber dual tail-boom setup with large tail and dual rudder control surfaces for controlling large weight shifts in towing operations. Need to make fuselage, add motor etc and I am not sure when (if) it will be finished.


    Do you have some info on the tests you did?



  • We did a lot of work with this about 5 years ago. It does work and well. Don’t you think the step is a bit large or did you base that off something your read? Nice work! Looking forward to the results.

  • This is a Kline Fogleman type 3 wing. http://en.wikipedia.org/wiki/Kline_Fogleman_airfoil

    You can see several NASA publications about tests that have been done and a more popular scientific coverage here: https://www.youtube.com/watch?v=6H-s7yuJcwk&feature=player_embed...

    More info and tests: http://www.rcpowers.com/forum/blog.php?b=20/


    The basic idea is that a vortex is generated behind the steps and that this vortex causes the airflow to not de-attach from the surface of the vortex. This causes less drag. The wing also is claimed to have a wider CG range, a wider lift generating AOA range and several other benefits. Some authors claim it generates more drag, but that is disputed from several other sources. The wing has not been used extensively in commercial aicraft, but many RC aircraft builders have tested this wing. I intend to use it in an UAV project.
  • Moderator
    There does not seem to be any sweep on that, is it a plank???
  • T3
    Does that wing shape have a name? Any more info on it? White papers?
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